Process for preparing branched primary sulfate esters



Patented Nov. 24;, 1953 htthttii PROCESS FOR PREPARING BRANCHED PRIMARY SULFATE ESTERS Herbert K. Wiese, Cranford, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application April 27, 1950, Serial No. 158,589

7 Claims. (Cl. 260-460) This invention is concerned with. the prepare.

tion of branched primary sulfate esters by combining ethylene with another olefin in the presence of concentrated sulfuric acid. More particularly, the invention involves the reaction of ethylene with another mono-olefin, particularl, a tertiary olefin, in the presence of concentrated sulfuric acid to produce a branched primary sulfate ester.

It is well known that a primary sulfate este cannot be produced from an olefin and sulfuric acid, with the exception of ethyl sulfate from ethylene. In all cases only a secondary sulfate ester will result. Tertiary sulfate esters are believed to be formed but cannot be isolated. invention involves a process for producing branched primary sulfate esters having carbon atoms or more by combining ethylene with another olefin (co-reactant) in the presence of 80-100 weight per cent sulfuric acid, preferably 90-98 weight per cent sulfuric acid.

The reaction scheme may be generalized as follows:

Therefore this process claims the production of v alkylated ethyl sulfates in which the co-reactant is always attached to the carbon atom adjacent to the carbon atom containing the sulfate group. More specifically, when using, for example, iscbutylene as the co-reactant the overall reaction can be written as follows:

Z-Lertiary butyl ethyl sulfate-l The co-reactant is a tertiary, secondary or primary olefin or mixtures thereof selected from the aliphatic and/or alicyclic series. Its molecular weight can range from 42 to 420 (C3 to C) and higher. It is also possible to use a diolefin as coreactant and obtain a dihydroxy compound ccntaining either two primary hydroxyl groups or one primary and one secondary depending on reaction conditions.

The reaction itself is carried out by simuL taneously contacting sulfuric acid of 80-l60 weight per cent strength, preferably 90-98 weight per cent, with ethylene and the olefin co-reactant at temperatures ranging from -25 C. to +80 (7., preferably -15 C. to +45 C. The optimum results are obtained by maintaining an ethylene partial pressure of -4000 p. s. i. g., preferably 100-250 p. s. g, over the sulfuric acid and continuously feeding the co-reactant to the reactor. In some cases it is of particular advantage to use temperatures below the critical temperature of ethylene C.) and sufiicient pressure to main tain ethylene in the liquid form.

The rate of self-polymerization of the co-reactant, particularly the lower molecular weight co-reactants, and more particularly the tertiary olefins, is known to be faster than the rate of combination of the co-reactant with ethylene. Therefore, in order that the combination of the (lo-reactant with ethylene predominates, it is important to maintain a high ethylene/co-reactant ratio in the reaction zone. This is accom-' plished by using (1) ethylene under pressure and (2) by regulating the addition of the co-reactant to the ethylene and sulfuric acidv in the reaction zone, in such a manner, that the rate of addition is essentially equal to the rate of combination of ethylene with the co-reactant. For example, with such co-reactants as isobutylene or 2-meth ylpentenes the rate of addition of the co-reactants is so maintained that the molar ratio of ethylene/isobutylene or Z-methylpentenes in the reaction zone is greater than 50:1. This ethyleneco-reactant ratio in the reaction zone can vary widely depending on the co-reactant and reaction conditions such as temperature, pressure, acid concentration. etc. With such co-reactants, as for example, Car-polypropylene, tetra-isobutylene or any other olefin where the rate of self-polymerization is negligible, ethylene/co-reactant ratios less than 50:1 can be employed.

The desired branched primary sulfate ester is produced by adding the pure olefin to the reactor containing the sulfuric acid of the appropriate strength, and ethylene under the desired pressure. To assure high yields of primary sulfate ester it is preferred to have an inert hydrocarbon diluent present in the reaction zone particularly when employing the lower molecular weight olefins or co-reactants. However, this diluent may be dispensed with when employing the higher molecular Weight olefins such as (312-024 olefin polymers, etc. In the latter case the higher molecular weight olefins themselves act as the diluent since their rates of self-polymerization are negligibly low. The inert diluent is any non-reactive organic material, such as saturated aliphatic and/or alicyclic hydrocarbons and any derivative thereof, provided they are substantially chemically inert toward sulfuric acid under the conditions employed. Such saturated hydrocarbons are preferably n-paraffins but iso-paraiiins are also useful. However, when employing an inert diluent consisting predominantly of a branched chain paraffin, it is desirable that the parafiin have the same carbon skeleton structure as the olefinic co-reaotant. Otherwise. a decrease in theselectivity to the desired alcohol may res e lnm a i Qtine d i hit suliur acid that is most advantageous in either a batch or continuous type operation ranges from :1 to 1:10, preferably 3:1 to 1:1.

It is, of course, understood that wheuemploying an inert diluent good intermixing between the acid phase and the diluent phase ispartipularhf. essential. The diluent may. b e i f d esl d, intro; duced to the reactor prior to feeding the co-reactant. It is also possible to use a co -reactant feed consisting of a mixture of a co-reactantand, an inert diluent. Such a feed may, for example, comprise a selected fraction derived from a cracked petroleum stock containing the desired co te c a t. an a urate h ro a bon. Q 2 1?- Qca-r ns, When. us g di uted. tileacta eed i s a anta e us e c tinuo s y thdraw part of theinert diluent in ordenthatthe desired diluent/sulfuric acid ratio. is maintained in the. reaction zone. This. is. accomplished in. one -ma n n e r, for example, ina continuous type operation, by introducing the co-reactant feed at the bot-.. tom of a reactor containing. the sulfuric acidin: termixed with the inert diluent, continuously. withdrawing some of the co -.reactant-free diluent from the topof the reactor- Thedesired ethylene partial pressure is, of course, maintained. in, the reaction zone.

The acid layer iswithd-rawn. fromthereaction. zone after an. extractstrength of 0.2 to 1.0, pref; erably about 0.5, hasbeenobta-ined. The extract strength is defined as moles. of produced. olefins, that is, theolefin derived from, a combination of ethylenev with the co-reactant. per molev of S111". furic acid. Although the primary suliates, pro. duced accordingto this invention find most ap-. pl c in the us of. th r er vat ves. t e fates themselves are useful products and may. be s l e as. s ch- The; lo e mol cular. We ht branched. primaryalkyl sulfates are recoyeredl in. the lo ng mann r. 2h? mixture Qi sulieie and. s lf r c i neut a ize with cau i Q ar o a here a he s lf e is. war anted. t h sodium s l T e al s xtr ted. ith. c h l. the solvent removed the salt; reeacidified to. pr uc t suli -t Th 3.3=dime. t a e-l isolate n. such a m nner. is i y liqui TabZe.- Alkyl'ation of ethylene in thepresence ofsulfuric acid to produce aZkg/Zc ted ethanols which has a en ii at .Qf-Q-. :eb. 1 & .1 and a refractive index at 20 C. of about 1.42. The neutralization equivalent was 188 (theoretical 182.2). The higher molecular weight sulfates ;;Qi- 2 may be extracted from the sulfuric acid directlyby'means of a solvent such as an aliphatic hydrocarbomfor example, hexane which may be i exuoyed-Icy-distillation, leaving the purified alkyl fate The primary sulfates produced according to this inyention can be converted to many useful products. For example, upon hydrolysis with Water; using well established procedures, branched primary alcohols are obtained. To illustrate this, he results o runs. are late bel Ijhest; batch runs; were, made with 95.5 weight percent sulfuric acid at T15- C. and with nheptane as the inert diluent (volume ratio of heptane/sulfuric acid 6 :1). An ethylene partial pressureof about 11 5 p. s. i. g. was maintained in the. reactor. In both runs the pure oo-reactant was fedto the, reactor over a 3-hour period. An extract strength of about 0.5 was thus obtained, The, primary. sulfate ester was then hydrolyzed with water and the corresponding alcohols iso--. lated byknown methods.

Moi percent Olefin co-rcactunt Alcohol obtained co-rcactam) 3,3-dimothylbuianol-l Approxfifm.

Isohutylcno I fl-rlimothylhcxanol-L App1oX.1l5.0.

Rull N0 714-5 Tifi-l) 714-19 714-27 714-35 714-47 714-43 714-6 3 Temperature ol' run, C -15 -..l.)- -15 T17. Charge: j

Ethylene-pressure, p,si 115 115 115.

gage. Mols of H SO; 1.3 .3 .1 0.0. Olcfinuseri co-r W lso-butyl- Z-methyl- Ilexcnes.

-yclo- H one. 1) c n tgenteneh ones.

4 n -lfenti ne n-fle rgu e n-Tlepn-Hep-, n -Hep- 2;1nethyl 11-1101) Lane tone. tune pent-one. tam Volume ratio diluent/ 1;. ..-.5 ..i'6.5 6.5 6.5 6.5 6.5 2.0. Z M 1 Recovered:

Ethanol, reels 0.19 0. 17 Alkylated ethanols, type Alcohiofl'f. Its Isohexy l Alkylated ethan0ls,1n'o1s 0.095 0. Higheralcohol, primary Et cna fiers ET? Moi. percent yield of alcohol;

approxA Cone, su

1 Alcohol by acetylation of cuts.

4 Based on co-reactant charged.

111 1c ci -36%. determmed by fractionating crude alcohol obtained from hydrolysis oiaeid phase and determining hydroxyl content 5 Infra-red shows prod ct to be a primary alcohol containing a cyclohexyl or cyclopentyl typo ring. 3,3-d1mcth3llbutauol-1, B.P. 142.5 C. 111, 1.4142. Literature valuc142.5 O. 111, 1.4143.

98.0% pure. b Infra-red indicates primary hydroxyl.

c 80.0% 2- nethylpcntene-2, 20.0% 2-methylpeutcnc-l. Hexene out, B,

P. (El-71 0,, 83.8% unsaturates, ratio of tertiary/secondary 3.5/1.

e Alcohols derived from polymerized co-reactant and ethylene.

yield (based on.

The acetate derived from 3,3-dimethylbutanol and glacial acetic acid by the usual esterification process is useful as a lacquer solvent. The oli-octyl phthalate ester derived from phthalic anhydride and the branched chain ethanol can be employed as a plasticizer for polyvinyl chloride type plastics and others.

In addition to hydrolyzing the primary sulfates to the corresponding primary alcohols, the sulfate esters containing from about 12 to 20 carbon atoms can be neutralized with an alkaline base or carbonate to produce a water-soluble detergent. For example, the sodium salt of the sulfate ester derived from Ora-polypropylene and ethylene was found to possess definite detersive properties (sodium salt of C14-alkyl sulfate).

Furthermore, the primary sulfate esters may be reacted with hydrogen halides such as HI, I-IBr, HCI, or HF to produce the corresponding primary organic halide, according to the equation:

where R represents a branched primary alkyl radical.

The production of the primary sulfate ester is carried out according to conditions previously recited. The hydrohalogenation step is carried out as follows:

The acid extract layer comprising the primary sulfate ester is treated with an anhydrous hydrogen halide at temperatures ranging from C. to 100 0., preferably about 25 C. to 50 C. The primary halides will form by passing the anhydrous hydrogen halide into the acid extract layer. However, it is advantageous, in some cases, to maintain a hydrogen halide pressure ranging from 1 to 4 atmospheres, preferably about 1 to 2 atmospheres, over the acid layer. The organic halides are insoluble in sulfuric acid and therefore will settle out as a separate layer, thus making their separation a simple mechanical operation. It is also possible to have an inert solvent present during the hydrohalogenation to dissolve the organic halide as produced. This solvent for example may be the same as the saturated hydrocarbon present in the reactor during the production of the primary sulfate ester. When using the saturated hydrocarbon from the reactor it is necessary to free it of ethylene prior to the hydrohalogenation step.

The primary sulfate ester will undergo other reactions with suitable reagents, such as, ammonia to form primary amines, alcoholysis to form other esters and mixed neutral sulfates, and the like. Heating results in the acid sulfate esters decomposing to alpha olefins which are valuable in many chemical syntheses.

What is claimed is:

1. A process for producing a branched primary alkyl sulfate whichlcomprises reacting ethylene with a tertiary C's-Cm olefin in the presence of 90-98 weight per cent. sulfuric acid at a temperature of 25 C. to +80 0., and at an ethylene partial pressure of -1000 p. s. i. g. whereby a branched primary alkyl sulfate is obtained having two more carbon atoms than the tertiary olefin reactant.

2. A process for producing 3,3-dimethylbutyl sulfate-1 which comprises reacting ethylene with isobutylene in the presence of 90-98 weight per cent H2804 at a temperature of 25 C. to C., and at an ethylene partial pressure of 100-250 p.s.1.g.

3. A process for producing 3,3-dimethylhexyl sulfate-1 which comprises reacting ethylene With a Z-methylpentene in the presence of -98 weight per cent H2504 at a temperature of 25 C. to +80 0., and at an ethylene partial pressure of -250 p. s. i. g.

4. A process according to claim 1 in which the reaction is carried out in the presence of an aliphatic hydrocarbon diluent.

5. A process according to claim 1 in which the ratio of ethylene to the olefin in the reaction mixture is greater than 50:1.

6. A process according to claim 2 in which the reaction is carried out in the presence of a normal parafiin as a diluent.

7. A process according to claim 2 in which the reaction is carried out in the presence of hexanes.

HERBERT K. WIESE.

References Cited in the file of this patent UNITED STATES PATENTS Number 

1. A PROCESS FOR PRODUCING A BRANCHED PRIMARY ALKYL SULFATE WHICH COMPRISES REACTING ETHYLENE WITH A TETIARY C3-C30 OLEFIN IN THE PRESENCE OF 90-98 WEIGHT PER CENT SULFURIC ACID AT A TEMPERATURE OF -25* C. TO +80* C., AND AT AN ETHYLENE PARTIAL PRESSURE OF 50-1000 P. S. I. G. WHEREBY A BRANCHED PRIMARY ALKYL SULFATE IS OBTAINED HAVING TWO MORE CARBON ATOMS THAN THE TERTIARY OLEFIN REACTANT. 